Struck-by injuries and fatalities are prevalent in the construction industry, specifically at road construction work zone sites. Although the cause of vehicle-worker fatalities is not reported, one can rationally suggest that they are due to a number of factors including the inattentiveness of the driver and/or worker and the failure of the driver to obey traffic laws. Dynamic message signs (DMS) have been shown to effectively influence driver behavior. However, in order for the signs to effectively influence speed reduction and compliance in work zones, the signs must draw the attention of the driver, the driver must decide to process the message of the sign, and the driver must decide to obey the posted speed limit. The ultimate goal of this research is to develop design standards for dynamic message signs in work zones to reduce the risk of struck-by incidents for construction workers. The specific aim is to determine the impact of sign content, frame refresh rate, and sign placement on driver behavior in work zones. It is expected that signs will be more effective under the following conditions: 1) signs that mention the presence of construction workers, 2) signs with moderate refresh rates, and 3) signs placed farther from the start of the work zone. Each of these factors will be tested in a project using a high-fidelity driving simulator with an integrated eye tracking system. A two (content) three (refresh rate) two (placement) full factorial design will be used to evaluate speed reduction, compliance rate, and eye movements. All independent variables (sign content, refresh rate, placement distance) will be within-subjects variables. Participants' gender, age, driving history, and safety attitude will also be evaluated t account for individual differences. A total of 50 participants will be included in the study. Each participant will complete twelve driving scenarios (one for each of the factorial combination of the experimental factors, counterbalanced across participants) in the driving simulator. During each scenario, participants drive in a four-lane divided highway setting and will encounter highway work zones throughout the scenarios. Driver behavior and attention before entering the work zone and upon entering the work zone will be evaluated to determine impact of the dynamic signs on speed and compliance. The proposed study will assist in lowering the incidence of struck-by incidents in work zones by identifying (and eventually implementing) effective sign designs for reducing driver speed and increasing compliance. Finally, the project will evaluate features of signs that can passively influence driver's visual attention to the dangers experienced by construction workers, supplementing current speed reduction enforcement activities.